Various methods, systems and apparatus relating to the present invention are disclosed in the following co-pending applications filed by the applicant or assignee of the present invention simultaneously with the present application:
NPA001US, NPA002US, NPA004US, NPA005US, NPA006US, NPA007US, NPA008US, NPA009US, NPAO10US, NPA012US, NPA016US, NPA017US, NPA018US, NPA019US, NPA020US, NPA021US, NPA030US, NPA035US, NPA048US, NPA075US, NPB001US, NPB002US, NPK002US, NPK003US, NPK004US, NPK005US, NPM001US, NPM002US, NPM003US, NPM004US, NPN001US, NPP001US, NPP003US, NPP005US, NPP006US, NPP007US, NPP008US, NPP016US, NPP017US, NPP018US, NPS001US, NPS003US, NPS020US, NPT001US, NPT002US, NPT003US, NPT004US, NPX001US, NPX003US, NPX008US, NPX011US, NPX014US, NPX016US, IJ52US, IJM52US, MJ10US, MJ11US, MJ12US, MJ13US, MJ14US, MJ15US, MJ34US, MJ47US, MJ58US, MJ62US, MJ63US, MJ64US, MJ65US, MJ66US, PAK04US, PAK05US, PAK06US, PAK07US, PAK08US, PEC01US, PEC02US, PP01US, PP02US, PP03US, PP04US, PP07US, PP08US, PP09US, PP10US, PP11US, PP12US, PP13US, PP15US, PP16US, PP17US.
The disclosures of these co-pending applications are incorporated herein by cross-reference.
This invention relates to an ink jet printhead. More particularly, the invention relates to a nozzle guard for an ink jet printhead.
Our co-pending patent application, U.S. patent application Ser. No. to be advised when known (identified temporarily by our Docket No. IJ52) discloses a nozzle guard for an ink jet printhead. The array of nozzles is formed using microelectromechanical systems (MEMS) technology, and has mechanical structures with sub-micron thicknesses. Such structures are very fragile, and can be damaged by contact with paper, fingers, and other objects. The present invention discloses a nozzle guard to protect the fragile nozzles and keep them clear of paper dust.
According to the invention, there is provided a nozzle guard for an ink jet printhead, the nozzle guard including a body member mountable on a substrate which carries a nozzle array, the body member defining a plurality of passages through it such that, in use, each passage is in register with a nozzle opening of one of the nozzles of the array and the body member further defining fluid inlet openings for directing fluid through the passages, from an inlet end of said passages, for inhibiting the build up of foreign particles on the nozzle array.
In this specification the term xe2x80x9cnozzle xe2x80x9d is to be understood as an element defining an opening and not the opening itself.
The nozzle guard may include a support means for supporting the body member on the substrate. The support means may be formed integrally with the body member, the support means comprising a pair of spaced support elements one being ranged at each end of the body member.
Then, the fluid inlet openings may be arranged in one of the support elements.
It will be appreciated that, when air is directed through the openings, over the nozzle array and out through the passages, a low pressure region is created above the nozzle array which, it is envisaged, will inhibit the build up of foreign particles on the nozzle array.
The fluid inlet openings may be arranged in the support element remote from a bond pad of the nozzle array.
The invention extends also to an ink jet printhead which includes a nozzle array carried on a substrate; and
a nozzle guard, as described above, mounted on the substrate.
The invention extends still further to a method of operating an ink jet printhead, as described above, the method including directing fluid through the fluid inlet openings of the nozzle guard and through the passages to an outlet end of said passages for inhibiting the build up of foreign particles on the nozzle array.
Then, the method may include directing air through the passages irrespective of whether or not ink droplets are being ejected through the passages.
The method may include directing fluid through the passages at a rate different from that at which the ink droplets are ejected through the passages. Preferably, the method includes directing the fluid through the passages at a rate lower than that at which the ink droplets are ejected through the passages. In this regard, the air may be charged through the passages at approximately 1 mi/s. In use, ink is ejected from the nozzle opening of a nozzle of the array at approximately 3 m/s and travels through the passage at approximately that velocity.